#define _CRT_SECURE_NO_WARNINGS

#include <stdio.h>

int HmsToS(int h, int m, int s)
{
	int sum = 0;
	sum = h * 3600 + m * 60 + s;
	return sum;
}

void PrintTime(int s)
{
	int H, M, S;
	H = s / 3600;
	M = (s - H * 3600) / 60;
	S = s - H *3600 - M * 60;
	printf("%02d:%02d:%02d\n", H, M, S);
}

int main()
{
	int h1, h2, m1, m2, s1, s2;
	int hms1, hms2;
	int minus;
	while (scanf("%d:%d:%d", &h1, &m1, &s1) != EOF)
	{
		scanf("%d:%d:%d", &h2, &m2, &s2);
		hms1 = HmsToS(h1, m1, s1);
		hms2 = HmsToS(h2, m2, s2);
		minus = hms2 - hms1;
		PrintTime(minus);
	}
	return 0;
}